If you've kept tabs on CES at all this year then you'll notice there are plenty of manufactures beginning to develop 4K TV sets. Full aperture 4K clocks in at 4096x3112. Absolutely massive. Even the Quad HD spec at 3840x2160 is ginormous. So isn't bigger always better?
I think my biggest objection so far is that the content producers are still coming around to 1080p. The world (i.e. consumers) are not ready for 4K. There is no deliverable content at that resolution. There are plenty of cameras that shoot 4K, 5K or more, but actually delivering that to someone's home is not possible with today's technology. Once the specs get bumped for Blu-Ray, HDMI, stereo receivers, internet broadband speeds, etc. then we can talk. But if you're looking for a more technical reason why 4K just isn't necessary then look no further. Geoffrey Morrison over at c|net wrote up a solid piece that mathmatically illustrates why 4K doesn't really have any impact in our 2012 world.